2eyn
Crystal structure of the actin-binding domain of human alpha-actinin 1 at 1.8 Angstrom resolution
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OverviewOverview
Alpha-actinin belongs to the spectrin family of actin crosslinking and, bundling proteins that function as key regulators of cell motility, morphology and adhesion. The actin-binding domain (ABD) of these proteins, consists of two consecutive calponin homology (CH) domains. Electron, microscopy studies on ABDs appear to support two competing actin-binding, models, extended and compact, whereas the crystal structures typically, display a compact conformation. We have determined the 1.7A resolution, structure of the ABD of alpha-actinin 1, a ubiquitously expressed isoform., The structure displays the classical compact conformation. We evaluated, the two binding models by surface conservation analysis. The results show, a conserved surface that spans both domains and corresponds to two, previously identified actin-binding sites (ABS2 and ABS3). A third, and, probably less important site, ABS1, is mostly buried in the compact, conformation. However, a thorough examination of existing structures, suggests a weak and semi-polar binding interface between the two CHs, leaving open the possibility of domain reorientation or opening. Our, results are consistent with a two-step binding mechanism in which the ABD, interacts first in the compact form observed in the structures, and then, transitions toward a higher affinity state, possibly through minor, rearrangement of the domains.
About this StructureAbout this Structure
2EYN is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of the actin-binding domain of alpha-actinin 1: evaluating two competing actin-binding models., Borrego-Diaz E, Kerff F, Lee SH, Ferron F, Li Y, Dominguez R, J Struct Biol. 2006 Aug;155(2):230-8. Epub 2006 Apr 25. PMID:16698282
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